Conventional radiography and fluoroscopy is a well known art. Conventional radiographic and fluoroscopic (R&F) X-ray systems typically comprise a X-ray table upon which a subject under examination is placed, a source of radiation for propagating x-rays through the subject under examination, an imaging system to convert a pattern of X-radiation eminating from the subject into a corresponding visible light image, a viewing device to display the light image and a spotfilmer for making a film record of the viewed image.
In tiltable type X-ray tables a flat topped elongated table body is pivotally connected to a base or pedestal so that it can be tilted in either direction from is normal position in which the patient-supporting top surface is horizontal. The table body pivots about an axis parallel to its top and perpendicular to its length. In so-called 90/90 tables, the table body is tiltable in either direction 90.degree. from the horizontal. The tilting permits examination of the patient in any angular position between these two rxtremes. Other tables have a body which is tiltable in one direction from the horizontal to a 90.degree. position and in the other direction to a so-called Trendelenburg position wherein the angle of tilt is limited to an angle of 45.degree. or less from the horizontal.
Such table assemblies typically include a tower assembly which is movably carried by the table body. The tower assembly is carried in a path transverse to the longitudinal extent of the table body by a carriage. The carriage is also movable longitudinally relative to the table body along two rails mounted in the table body. The X-ray source is mounted to the carriage and is housed in the table body. The tower assembly also supports radiation sensing devices such as the spotfilmer and imaging system. The radiation sensing devices are movable with respect to the table assembly in a vertical direction. The imaging system typically includes an image intensifier tube and associated viewing medium for viewing the image intensifier tube output.
The spotfilmer is commonly supported by the tower assembly in spaced relation above a patient examining surface defined by the X-ray table top and in alignment with the X-ray source. The combination of the carriage and tower assembly permit the spotfilmer and imaging system to move in the transverse, longitudinal and vertical directions with respect to the table body.
The X-ray source is mounted to the carriage such that the longitudinal alignment of the source with the radiation sensing devices is maintained during movement along the entire table body length.
An example of one such tiltable X-ray table can be found in U.S. Pat. No. 4,197,465 issued to Schneider, owned by the present assignee and which is expressly incorporated herein by reference.
The three rectilinear paths of travel described above permit the spotfilmer/imaging system combination to be moved to any selected position over the table top and to any selected distance from the top within the limits of the respective paths of travel.
The table top employed in such a system is commonly movable with respect to the table body. Two-way tops and four-way tops are frequently used. A two-way top provides for two-way motion along the longitudinal extent of the table body. A four-way top provides for two-way motion along the longitudinal extent of the table body plus two-way motion in a path transverse to the longitudinal extent. The table top is comprised of a rigid metal frame covered by a radiolucent material such as a plastic laminate.
In operation, the patient undergoing an examination is placed on the table top typically in a prone position. The movable top is adjusted to precisely position the patient with respect to the x-ray tube and imaging systems.
To insure that interference between the table top and table body does not occur during top movement, a clearance space is provided between the table top and table body. It is desirable to keep this space at a minimum, but due to tolerances associated with the componentry provided for table top motion, a gap in the order of 0.5 inches is typical.
Because of the various table top and table body motions that may occur during a patient examination, patients lying on the table top surface may feel insecure or unstable and may grasp a secure structure for balance. If the patient is placed on the table top in a prone, face-down position, the patient frequently brings his/her hands up above his/her head and may find an end of the table top a convenient location to place his/her hands. Grasping the end of the table top in this manner may cause inadvertent placement of fingers in the clearance space between the table top and table body. If further patient positioning is necessary and the table top is moved, particularly in the longitudinal direction, the patient's fingers may interfere with the relative motion of the table top with respect to the table body.
It is therefore an object of this invention to overcome the above referenced problems and others by providing an improved patient support structure.